<template>
  <div id="app">
    <!-- 路由占位符 -->
    <router-view />
  </div>
</template>
<script>
export default {
  name: 'app',
  // 防止数据丢失
  created () {
    //在页面加载时读取sessionStorage里的状态信息
    if (sessionStorage.getItem("store") ) {
      this.$store.replaceState(Object.assign({}, this.$store.state, JSON.parse(sessionStorage.getItem("store"))))
    }
    //在页面刷新时将vuex里的信息保存到sessionStorage里
    window.addEventListener("beforeunload",()=>{
      sessionStorage.setItem("store", JSON.stringify(this.$store.state))
    })
  }
}
</script>
<style>
</style>
